1. Field of the Invention
The present invention relates to a method of resetting a substrate processing apparatus, a storage medium storing a program for implementing the method, and a substrate processing apparatus, and in particular relates to a method of resetting a substrate processing apparatus after maintenance, and a storage medium storing a program for implementing the method.
2. Description of the Related Art
Generally, a substrate processing system that carries out predetermined processing such as film formation or etching on semiconductor wafers (hereinafter referred to as “wafers”) as substrates is comprised of a processing chamber (substrate processing apparatus, hereinafter referred to as “P/C”) in which a wafer is housed and subjected to the predetermined processing, an atmospheric system transferring apparatus that removes wafers from a wafer cassette, which is a sealed container housing a predetermined number of wafers, and a load lock chamber that is disposed between the atmospheric system transferring apparatus and the P/C and transfers wafers in and out between the atmospheric system transferring apparatus and the P/C.
In such a substrate processing system, the P/C has a cylindrical chamber (hereinafter referred to as “chamber”), a wafer being subjected to the desired processing such as etching in the chamber using a plasma or the like. However, the plasma in the chamber during the etching does not only etch the wafer, but also causes wear of component parts of the chamber, and furthermore causes production of reaction products such as a deposit. The reaction products become attached to surfaces of component parts, and hence every time a predetermined processing time period has elapsed, it is necessary to open a lid that separates the inside of the chamber from the outside, and carry out maintenance such as replacing worn out component parts in the chamber or cleaning component parts on which reaction products have become attached. Once the maintenance has been completed, the lid is closed, and resetting work involving reducing the pressure in the chamber and so on is carried out on the P/C.
During the P/C resetting work, the state of transfer of wafers and the wafer surface etch rate are checked. In the case, for example, that the etch rate exhibits an abnormal value, it is necessary to carry out a chamber leakage check, or open the lid of the chamber and recheck inside the chamber, checking for example whether or not a component part is missing or out of place, whether or not there is a component part installation defect, or whether or not there is a component part cleaning defect. There has thus been a problem that the P/C resetting work takes much time.
In recent years, there has thus been developed a method in which, because the state of plasma generation in the chamber becomes unstable if a component part installation defect arises in the chamber, the output of a high-frequency power source that applies high-frequency electrical power in the chamber is monitored so as to detect abnormalities in the P/C. In this method, it is detected whether the high-frequency power source has reached a stable state by comparing results of multivariate analysis on a plurality of types of measured data for the high-frequency power source measured when the state of application of the electrical power by the high-frequency power source has become stable (hereinafter referred to as the “normal model”) with results of multivariate analysis on the same measured data measured upon start-up of the P/C (see, for example, Japanese Laid-open Patent Publication (Kokai) No. 2002-18274).
According to this method, mistakes in the installation of component parts in the chamber and so on can be detected without opening the lid of the chamber, and hence compared with conventional P/C resetting work, the time required for resetting the P/C can be reduced.
However, according to the method described above, in which the output of the high-frequency power source is monitored so as to detect abnormalities in the P/C, multivariate analysis must be carried out. A method of selecting the measured data to be used in the normal model has not been established, and hence there is a problem that when setting thresholds for comparison, universality of the normal model cannot be secured, and the P/C abnormality judgment cannot be carried out accurately.
Moreover, in the multivariate analysis, each piece of measured data is standardized, and hence the multivariate analysis results are not absolute values. When setting a given multivariate analysis result as a threshold, because the multivariate analysis result is not an absolute value, it is difficult for workers to understand the effect that a variation in the measured data will have on the multivariate analysis results. As a result, there is a problem that the workers' subjectivity enters into the setting of thresholds, and hence again the universality of the normal model cannot be secured, and the P/C abnormality judgment cannot be carried out accurately.
Furthermore, the environment in the chamber changes between before and after maintenance, and hence the normal model must be reset every time maintenance is carried out. There is a problem that this takes much time, and hence a decrease in the utilization ratio of the P/C still cannot be prevented.